A solution of N-[(4aR,7aR)-7a-(2-thienyl)-4a,5,6,7-tetrahydro-4H-pyrrolo[3,4-d][1,3]thiazin-2-yl]benzamide (7.7 g, 22.4) and N,N,N′,N′-tetramethylguanidine (3.39 mL, 26.9 mmol) in dimethyl sulfoxide (61 mL) is treated with 5-fluoro-2-chloropyrimidine (2.25 mL, 23.54 mmol) and the resulting solution is heated at 50° C. for 4 hours. The solution is cooled to room temperature and added to water (500 mL). The crude product is purified over silica gel using a 5 to 50% gradient of ethyl acetate/hexanes to give the title compound (7 g, 71%). ES/MS (m/e): 440 (M+H).
